Compositions and methods for circulatory stimulation and saluretic activity which employ 2-methyl-4-hydroxy-pyrido(2 3-d)-pyrimidine

ABSTRACT

PHARMACETUTICAL COMPOSITIONS CHARACTERIZED BY CIRCULATORY STIMULATING AND SALURETIC ACTIVITY COMPRISING 2-METYHYL4-HYDROXY-PYRIDO-(2,3-D)-PYRIMIDINE IN ADMIXTURE WITH A PHARMACEUTICAL CARRIER.

United States Patent Oflice 3,629,420 Patented Dec. 21, 1971 US. Cl.424251 19 Claims ABSTRACT OF THE DISCLOSURE Pharmaceutical compositionscharacterized by circulatory stimulating and saluretic activitycomprising Z-methyl- 4-hydroxy-pyrido-[2,3-d]-pyrimidine in admixturewith a pharmaceutical carrier.

The present invention relates to novel pharmaceutical compositionscharacterized by circulatory stimulating and saluretic activity and tomethods for using the same.

Z-methyl-4-hydroxy-pyrido- [2,3-d] pyrimidine has been described byKlisiecki et al. (Roczniki Chem., 3, 251- 256/1923). However, its use asa pharmacological agent has not been suggested or investigated.

It is known that some pyrido-pyrimidine derivatives having somewhatsimilar structures are antagonists of folic acid and of the nucleicacids and can be used effectively as diuretics and bactericides. Closelyanalogous pyridopyrimidines are characterized by central nervousdepressive and hypnotic properties, i.e. in their action, they resemblethe known hypnotic methaqualone hydrochloride from which they differmerely by the substitution of a carbon atom by a nitrogen atom (IndianJ. Chem, 4, 447/1966).

In accordance with the invention it has now, surprisingly been foundthat 2-methyl-4-hydroxy-pyrido-[2,3-d-1- pyrimidine not only possessesexcellent saluretic properties but also outstandingly good circulatorystimulating properties.

Almost without exception, the previously commercially availablecirculatory stimulants are sympathomimetics. The broadest fields of useof sympathomimetically-acting pharmaceuticals are in the regulation ofconstitutional hypotonic disturbances. Since, however, the knownsympathomimetics only have a relatively short period of activity, it isnecessary to prolong the duration of activity by the use of specialpharmaceutical depot formulations.

2-methyl-4-hydroxy-pyrido-[2,3-d]-pyrimidine is characterized by asurprisingly long period of activity so that it is no longer necessaryto utilize this compound in the form of a depot formulation.

Furthermore, it has been established, and this is to be consideredextremely advantageous, that 2-methyl-4-hydroxy-pyrido-[2,3-d]-pyrimidine, in contradistinction to the knownsympathomimetics, such as adrenaline or nor adrenaline, brings about,parallel, i.e., simultaneously with an increase in the heart minutevolume and an increase in the flow of blood through the kidneys, aconsiderable increase in natriuresis without, however, influencing theexcretion of potassium.

Thus according to the present invention, there are providedpharmaceutical compositions having circulatory stimulating and salureticactivity which contain, as active 0 ingredient,2-methyl-4-hydroxy-pyr1do-[2,3-d]-pyr1m1d1ne, 7

in admixture with a pharmaceutical carrier. The latter can be either asolid pharmaceutical carrier or diluent when intended for oraladministration, or as a suppository, or a sterile injectable liquidpharmaceutical carrier or diluent, when intended for intravenous,intraarterial or parenteral administration, or a liquid pharmaceuticalcarrier or diluent possibly in admixture with a sweetening and/orflavoring agent, when intended for oral administration.

The pharmaceutical compositions according to the present invention canbe utilized in any of the forms as conventionally used for oral orparenteral administration, such as tablets, dragees, capsules, syrups,solutions, suspension, drops, suppositories or the like. For thispurpose, the active compound is mixed with appropriate liquid or solidcarriers or diluents and then made up into the desired form ofadministration by any of the conventional techniques employed in theart.

As examples of solid carriers or diluents, there may be mentionedlactose, mannitol, starch, talc, methylcellulose, magnesium stearate andgelatine, to which, if desired, there can be added coloring materialsand/ or flavoring agents and/ or sweetening agents. As mentioned above,when the compositions are intended to be used as injection solutions,they must be sterile and are advantageously used in the form ofampoules.

The preferred liquid carrier is water, preferably containing at leastone stabilizer and/or solubilizer and/or buffer and/or viscosityregulator. Additives of this type include buffers, such as a tartrate orcitrate buffer, solubilizers, such as ethanol, stabilizers, such ascomplexforrning agents, for example, ethylene-diamine-tetraacetic acidand its non-toxic salts, and viscosity regulators, such as highmolecular weight polymers, for example, liquid polyethylene oxide.

In the case of the treatment of human beings, Z-methyl-4-hydroxy-pyrido-[2,3-d]-pyrimidine is usually administered orally at adosage level of 10-200 mg. and intravenously at a dosage level of 5-100mg. In these dosage ranges, besides an optimum saluretic action, thereis also achieved a sufficient hypertonic action and a positive inotropicaction. As the active material is orally well resorbed, intravenousadministration is only preferred in those cases in which a rapidincrease in blood pressure is required or in which, for other reasons,oral administration of medicaments is contraindicated.

The administration of the 2-methyl-4-hydroxy-pyrido-[2,3-d]pyrimidine-containing compositions according to the presentinvention is especially indicated in cases of hypotonic regulationdisturbances in which it is desired to obtain a long-lasting increase ofthe blood pressure and, also at the same time, an increase in the flowof blood through the kidneys.

In order to unequivocally demonstrate the circulatorystimulating andsaluretic activity of 2-methyl-4-hydroxypyrido-[2,3-d]-pyrimidine, thefollowing pharmacological experiments were carried out.

(I) CIRCULATORY STIMULATION IN DOGS (1 Blood pressure and heart rate ofawake normotonic dogs Method-4 beagles, each having a weight of 8-15 kg.were used as experimental animals. Catheters were introduced via thearteria or vena femoralis into the abdominal aorta or into the caudalcavity 'vein and there implanted. 1O mg./-kg. 2methyl-4-hydroxy-pyrido-[2,3-d]-pyrimidine, dissolved in physiologicalsaline, were then intravenously injected into the dogs in a total amountof 3 4 4 ml. The results obtained are set out in Table I whichchronically implanted in the aorta thoracalis; the presfollows: I suremeasurement was carried out using arterial femoralis TABLE I.BLOODPRESSURE AND HEART RATE OF AWAKE, NORMOTONIC DOGS FOLLOWING THEADMINISTRATION OF 10 MG./KG. 2-METHYL4HYDROXY-PYRIDO-[2,3d]-PYRIMIDINETime after intravenous injection (in minutes) Dog No. K 5 15 30 60 90120 150 180 210 240 270 300 330 360 BOnnLHg) 157 80 78 80 94 100 110 114118 100 88 102 86 84 78 88 m 82 87 91 100 106 102 108 111 109 98 102 9590 90 88 Fr (min. 157 92 112 84 120 114 108 99 89 86 88 114 92 100 104120 NOTE. =contro1 value; 51mm. Hg) =average blood pressure; Fr (min.)=iieart rate; Yd=average Results-4n the measurement period whichamounted catheters; and the heart rate was determined on the rapto 6'hours, the average blood pressure and the heart rate idly registeringphasie flow sequence. 10 mg./ kg. 2-methincreased by about 20%. 20yl-4-hydroxy-pyrido [2,3-d] pyrimidine were adminis- Circulator anal sisin awake do S tered by infusion at a rate of 1 mg./kg./mmute. The y y gperiod of measurement was extended over 6 hours. The Methd.Themeasurement of the heart minute volresults which were obtained are setout in Table 11 which ume in awake dogs was carried out using flowmeters follows:

TABLE IL-CIRCULATORY ANALYSIS IN AWAKE DOGS AFTER INFUSION OF 10 MGJKG.2-METHYL-4-HYDROXY-PYRID [2,3-d1-PYRIMIDINEInfusi0n velocity 1mg./kg./min.

Heart minute volume in percent Time Infusion Start End 5 15 90 120 150180 210 240 270 300 330 360 K mins. mins. mins. minst mins. mins. mins.mins. mins. mins. mins. mins. mins. mins. mins. mins,

Average m 100 96 104 101 106 101 118 105 103 100 100 98 104 109 107 119111 Heart beat volume in percent Time Infusion m B F 5 15 so so so 120150 180 210 240 270 300 330 360 K mins. mins. mins. mins. mins. mins.mins. mins. mins. mins. mins. mins. mins. mins. mins. mins Average- 10083 91 67 75 78 77 75 76 74 75 74 76 74 83 Heart rate Time Infusion StartEnd 5 10 5 15 30 (i0 120 150 180 210 240 270 300 330 360 K mins. mins.mins. mins. mins. mins. mins. mins. mins. mins. mins. mins. mins. mins.mins. mins.

Average 76 94 Average blood pressure in mm. Hg

Time

Infusion Start End K mins. mins. mins. mins. mins. mins. mins. mins.mins. ruins. mins. mins. mins. mins. mins. mins.

Averagm 110 115 113 119 119 126 141 143 134 TABLE IIContinued Peripheralresistance in percent Time Infusion Start End 5 120 150 180 210 240 270300 330 360 K mins. mlns. mins. mins. mins. mins. mins. mjns. mins.mins. mins. ruins. mins. mins. mins. mins.

Average 100 109 99 107 102 113 109 124 117 NOTE.I'11 the above 11,K=control val'ue. Results:-The alterations of the heart minute volume 5Results:After only 2 hours had elapsed, there was fall within the rangeof error of the method. As the most observed a constant potassiumexcretion but a marked noticeable action of2-methyl-4-hydroxy-pyrido-[2,3-d]- natriuretic effect, which is alsoexpressed in the Na/ K pyrimidine on the circulation, there is observeda gradual quotient. Simultaneously with the natriuresis, the volumeincrease of the average blood pressure. Furthermore, there of urineincreases by a factor of about 2. When a dosage is observed an increaseof the peripheral resistance of the 20 of 12.0 mg./kg. was used, thediuretic and natriuretic acorder of about 30% and a decrease of heartbeat volume of tion is optimal and, in the case of higher dosages,gradualthe same order. The heart rate increases up to the end of the 1ydecreases again. Within a period of 6 hours, the diuresis experiment byabout 20-30 beats per minute. If an attempt has increased by a factor of3, while no significant alterais made to find a relationship betweenthese circulatory {io r b d i th .N /K qu0tients parameters, then it isobvious to assume that the increase of 25 pressure can be attributed toan increase in the peripheral (b) Using oral administration resistance.It was to have been expected that in the case of a pressure increase inthe dog, a corresponding decrease Y 3 Y-P3 PY of the minute volume and fth hear r t uld f 110 dine was administered in the same form asdescribed above Surprisingly, however, there is observed an increase of30 in II(la) but via the oral route. The results which were rate, aswell as an unchanged heart minute volume. Thus obtained are set out inTable IV which follows:

TABLE IV.--INFLUENCE ON THE EXCRETION OF URINE AND ELECTRO- LYTES INRATS-O RALLY [n=nurnber of groups each of 5 rats] Excretion/kg. in thecourse of- 2 hours 6 hours mVal mVal Dosage, Ml. M1. rug/kg. n urine ClNa K Na/K urine 01 Na K Na/K it is established that2-methyl-4-hydroxy-pyrido-[2,3-d]- Results:The experiment results whichwere obtained pyrimidine has a positive chronotropic and a positive ino-45 corresponded substantially to those obtained in the case tropicaction. of intraperitoneal administration. From this, there can be (H)INFLUENCE ON THE EXCRETION OF IN appreciated that the compound isexcellently orally AND ELECTROLYTES resorbed- (1) Experiments on rats.(a) Using intraperitoneal 50 (2) Experiments on Using intravenousadmmlstratlon administration Meth0d:Female Sprague-Dawley rats eachhaving an M thank-Female beagles each having an avera e f s n e gaverage weight of 160 g were maintained in the a t g ht of 11.8 g. weremaintained 1n the fasting state condition overnight but were allowed anunlimited amount of drinking water.2-methyl-4-hydroxy-pyrido-[2,3-d]-py- 55 rirnidine in an 0.5% tylosesuspension (10 rnl./kg.) was then administered intraperitoneally. After2 hours had elapsed and again after 6 hours had elapsed, the animalsovernight but allowed an unlimited supply of drinking water.2-methyl-4-hydroxy-pyrido-[2,3-d1-pyrimidine was injected intravenouslyat a rate of 1 ml./kg. of an 0.5% glucose solution. After 2 hours hadelapsed and again bladders were pressed out and the volume of urine, aswell after 6 hours d p thfi urine Was Obtained directas the electrolyteexcretion, determined. The results of this 0 3 0m the bladder y means ofa Catheter, measured and experiment are described in Table III whichfollows: analyzed for its electrolyte content.

TABLE IIL-INFLUENCE ON THE EXCRETION OF URINE AND ELECTRO- LYTES 1NRATS-INTRAPERIIONEALLY [77=number of groups each of 5 rats]Excretion/kg. in the course 01- (b) Using oral administration TABLEV.INFLUENCE ON THE EXCRETION OF URINE AND ELECTROLYTES IN DOGS [n=numberof dogs in the group] Excretion/kg. in the course of 2 hours 6 hoursRoute of :11 Val m Val Dosage, adminis- Ml. mg./kg. n tration urine ClNa K urine 01 Na 1% Control. 8 p.o. 2. 2 0.1 0. 04 0. 1 4. 3 0.1 0.1 0.

ControL- 17 i.v. 1.9 0. 1 0. 1 0. 1 5.6 0.3 0.4 0.6 i.v. 2. 9 0.1 0. 20.1 11.1 0.3 0. 6 0.5 10 6 i.v. 2.7 0.2 0.3 0.1 17.8 1.0 1.1 0.5

Results:Exactly as in the case of rats, in the case of dogs, there isobserved a marked increase of natriuresis, of diuresis and of the Na/ Kquotients, whereas the kaliuresis was not affected.

(III) ACUTE TOXICITY Meth0d:--The acute toxicity was determined on NMRImice each having an average weight of 20 g. The LD was determinedfollowing a complete probit analysis. For this purpose, the2-methyl-4-hydroxy-pyrido- [2,3-d]-pyrimidine was administered asfollows:

(A) orally in 1% tylose; (B) intraperitoneally in water; (C)intravenously in 0.9% sodium chloride solution.

The results which were obtained are set out in Table VI which follows:

TABLE VI Route of Average lethal administration: dose (LD mg./kg. P.0.124 L13. 284 I.v. 204

The following examples are given for the purpose of illustrating thepresent invention but are in nowise to be construed as a limitationthereof.

EXAMPLE 1 Ampoule formulation 10 mg. 2-methyl-4-hydroxy-pyrido-[2,3-d-pyrimidine were dissolved in 1 ml. double distilled water, filled intowhite ampules and sterilized by heating for 20 minutes at 120 C.

10 mg. Z-methyl-4hydroxy-pyrido-[2,3-d]-pyrimidine were dissolved in 1ml. double distilled water, filled into white ampules and sterilized byheating for 20 minutes at 120 C.

EXAMPLE 2 Ampoule formulation 50 mg.2-methyl-4-hydroxy-pyrido-[2,3-d]-pyrimidine were dissolved in 2 ml.double distilled water, filled into white ampoules and sterilized byheating for 20 minutes at 120 C.

2 methyl 4 hydroxy pyrido [2,3 d] pyrimidine was mixed with lactose andmaize starch and the mixture granulated with a 10% maize starch paste.The granulate thereby obtained was passed through a sieve having a meshsize of 0.8 mm. Thereafter, the methyl cellulose, talc and magnesiumstearate were added to the granulate. The resultant mixture washomogenized and pressed into tablets having a diameter of 7.0 mm. and atotal weight of 140 mg.

EXAMPLE 4 Tablet formulation Mg.2-methyl-4-hydroxy-pyrido-[2,3-d]-pyrimidine Lactose 75 Maize starch 75Methyl cellulose 14 Talc 14 Magnesium stearate 2 The components as aboveset out were mixed together according to the procedure described inExample 3, the mixture homogenized and then pressed into tablets havinga diameter of 10.0 mm. and a total weight of 280 mg.

What is claimed is:

1. A pharmaceutical composition for use in stimulating circulatory andsaluretic activity comprising, in effective amounts, 2methyl-4-hydroxy-pyrido-[2,3-d] -pyrimidine and a pharmaceuticallyacceptable liquid carrier.

2. A pharmaceutical composition according to claim 1 additionallycontaining at least one member selected from the group consisting ofsolubilizers, stabilizers, buffers and viscosity regulators.

3. A pharmaceutical composition according to claim 2 wherein saidsolubilizer is ethanol.

4. A pharmaceutical composition according to claim 2 wherein saidstabilizer is a complex forming agent.

5. A pharmaceutical composition according to claim 2 wherein said bufferis a member selected from the group consisting of citrate and tartratebuffers.

6. A pharmaceutical composition according to claim 2 wherein saidviscosity regulator is liquid polyethylene oxide.

7. A pharmaceutical composition according to claim 1 additionallycontaining a coloring agent.

8. A tablet comprising a pharmaceutical composition according to claim 1in dosage unit form.

9. A pharmaceutical composition according to claim 8 adapted for oraladministration.

10. A pharmaceutical composition according to claim 9 comprising atablet containing 10 to 200 mg. of said 2- methyl-4-hydroxy-pyrido-[2,3-d] -pyrimidine.

11. A pharmaceutical composition according to claim 9 comprising adragee of said 2-methyl-4-hydroxy-pyrido- [2,3-d1-pyrimidine.

12. A pharmaceutical composition according to claim 9 comprising acapsule containing 10 to 200 mg. of said 2- methyl-4-hydroxy-pyrido-[2,3-d] -pyrimidine.

13. A pharmaceutical composition for stimulating circulatory andsaluretic activity comprising an effective amount of2-methyl-4-hydroxy-pyrido-[2,3-d]-pyrimidine in admixture with a solidpharmaceutical carrier.

14. A sterile injectible liquid pharmaceutical composition for use instimulating circulatory and saluretic activity comprising effectiveamounts of 2-methyl-4-hydroxypyrido- [2,3 -d] -pyrimidine.

15. An ampoule containing a composition as claimed in claim 14.

16. Composition as claimed in claim 15 wherein the composition alsocontains at least one of a coloring, sweetening and flavoring agent.

17. Method of treating hypotonic regulation disturbances andsimultaneously obtaining an increase of blood flow through the kidneyswhich comprises administering to a mammal in which such treatment isindicated as composition containing therapeutically effective amounts ofZ-methyl-4-hydroxy-pyrido-[2,3-d1-pyrimidine.

18. Method according to claim 17 comprising orally 10 administering saidcomposition containing 10-200 mg. of said 2-methyl-4-hydroxy-pyrido-[2,3-d] -pyrimidine.

19. Method according to claim 17 comprising parenterally administeringsaid composition containing 5-100 5 mg. of said2-methyl-4-hydroxy-pyrido-[2,3-d1-pyrimi- OTHER REFERENCES Klisiecki etal., Roczniki Chem., 3 251-251 (1023).

STANLEY I. FRIEDMAN, Primary Examiner P UNITED 311111-151x1115111011K312 1 CER'LIFICATE 01* .CQRREICTION' 3,629,420 I a December 21, 1911Patent No. I

Wo1fgang Schaumann; Karl Dietmann-and Klaus Hardebec It is certifiedthat error appears in the abovc idcntified patcntand tht said LettersPatent are hereby corrected as shown below:

001. 6, Table 1v, 4:511:11. down, 5th

. For 1.11. -rvead Col. 7. Table V Last-column, first item,. for "0.read- --0.2

Last columh, second item; 6: "0.;", rgad --0.1--

} 'Signed and sealed this 11th day of Ju1Y 1972. 2

(SEAL) Attest:

ROBERT GOTTSCHALK Commissioner of Patents:

EDWARD.M,FLETCHER,JR. Attesting Officer

